Some early inventions of this type with a toroidal cylinder are listed as follows: U.S. Pat. Nos. 19,967; 259,964 (also 5,6,7); 627,832; 1,266,605; 1,921,662. These patents are mainly historical references of this type, showing that there was a great interest in this type of invention from the very beginning. In fact, there probably was more interest in the early days due to the fact that steam was used almost exclusively then.
Another class of invention related to this invention is the toroidal cylinder type used to make an internal combustion type engine. The following patents and the references therein are examples of this type: U.S. Pat. Nos. 2,284,186; 3,644,069; 3,500,798; 3,876,342; 3,767,331; 3,895,893; 4,072,447; 4,239,465; 3,899,269; 3,909,162; 4,035,111; 4,334,841; 4,174,930; 4,462,775. This type of invention is described as having two or four pistons that oscillate back and forth in various motions to create the motions necessary for internal combustion. These inventions are of interest because they have toroidal cylinders with pistons.
Next there is a class of invention with toroidal cylinders in which the abutments or pistons turn to pass each other. The following patents are examples of this type: U.S. Pat. Nos. 1,921,662; 3,521,979; 3,782,850; 3,867,075. These patents are of interest because they imploy toroidal cylinders. The pistons or abutments turn by various means which are not of interest here.
The invention class most related to this invention is U.S. Pat. No. 4,076,471 and the references cited therein. This patent has a toroidal cylinder and a piston that is a toroidal section like this invention. Also, this patent uses the piston to open the cylinder abutment. However, this patent uses a disk to hold the piston whereas the invention described by the inventor does not. Most inventions of this type have used a disk which rotates in the center of the cylinder. One of the advantages of the new invention described by the inventor is that the disk of older inventions has been eliminated as further described in detail.
Other inventions of interest here are U.S. Pat. Nos. 3,080,722; 3,810,724; 3,865,522; 4,462,775. This group of patents has movable abutments that are moved by a piston.
The search of the U.S. patents did not find an invention that is similar to the described invention herein. To the knowledge of the inventor the described invention appears to be unique and the first of its kind.